Question: Let $f:\left[-\frac{\pi}{2}, \frac{\pi}{2}\right] \rightarrow A$ be defined by $f(x)=\sin x$. If $f$ is a bijection, write set $A$.
Solution:
$\because f$ is a bijection,
co-domain of $f=$ range of $f$
As $-1 \leq \sin x \leq 1$
$-1 \leq y \leq 1$
So, $A=[-1,1]$
